Wow, I was getting gasoline last week and this guy in a hemi truck pulled up in the next pump, get out of truck with engine running and started pumping gas. Would it not hurt him to turn off the engine? How risky is it with engine running? Oh, while waiting for the gas to fill up, he opened the door, popped the hood, and checked something in the engine bay

I rarely shut the car off. You have better chances of hitting the lottery than you do with anything happening when you fill up with the car running.

why take the chance when all it take is a press of a button to turn off/on the engine. If something does occured during your fueling session as a result of the engine running, how would you feel knowing all could have been avoided had you been more cautious. I don't know enough to say what the risk level is but all the combustion is well hidden inside the engine (I think) which validate your lottery theory.

Unless I plan on stealing gas right after fueling, I would have my engine running at all time at the gas station

Wow, I was getting gasoline last week and this guy in a hemi truck pulled up in the next pump, get out of truck with engine running and started pumping gas. Would it not hurt him to turn off the engine? How risky is it with engine running? Oh, while waiting for the gas to fill up, he opened the door, popped the hood, and checked something in the engine bay

It's safe to leave a diesel running while pumping, because it is much harder to ignite, compared to gasoline.
The reason you aren't supposed to pump while your car is running is the fear of creating a spark and igniting the gasoline. A spark isn't going to ignite diesel.
Gasoline has a Flash point of -40°F.
Diesel has a Flash point of 143°F.

Wow, I was getting gasoline last week and this guy in a hemi truck pulled up in the next pump, get out of truck with engine running and started pumping gas. Would it not hurt him to turn off the engine? How risky is it with engine running? Oh, while waiting for the gas to fill up, he opened the door, popped the hood, and checked something in the engine bay

All harmless. The turn off the engine thing has to do with old risks of a backfire ignighting fumes. With vapor recovery hoses and cars not backfiring, the problem is all but gone. I agree with Derek - you've got a better chance of hitting the lottery.

The temptation isn't so bad right now. Winter hasn't officially begun, and with such a mild fall , I've grown accustomed to killing my engine while at the gas pump and enjoying the breeze.

But in a few weeks, when temperatures are in the single digits and the ground is piled with snow, I won't even want to roll down the window to talk to the attendant, let alone shut off my engine for five minutes as I fill up.

Hmm . . . but that's the law, right? You can't have your engine running while pumping gas. You also can't smoke a cigarette or use your cellphone. At least, that's what all the warning signs at the gas station say.

Maybe it's about time we review service station rules and regulations. Are you legally required to turn off your engine at the pump, or is that merely a recommendation? You can't drive with an open beer in the front seat -- but how about a gallon of lawnmower gas sitting next to you? And what, really, is so dangerous about talking on your cellphone while fueling ?

The law says

The State Fire Marshal's office, not the police, is responsible for monitoring gas stations, so I called the Stow headquarters for answers.

As you would expect, smoking cigarettes at a gas station is a major safety hazard and is totally illegal (Code of Massachusetts Regulations, Chapter 527 ). Filling your tank while your engine's running? Also illegal.

"There's an ignition factor when you have the motor running," said George Nice, a code compliance officer with the fire marshal's office. "When you put the gas nozzle in the pipe, it could have a static effect. Vapors emitting from the gas tank could ignite. There could be a spark from the engine area. There are multiple reasons why" you shouldn't do it.

Nice acknowledged that the chance of an explosion is rare -- technologically advanced pumping equipment sucks away most vapors as gas is poured into your car -- but accidents can happen. The most famous local example, of course, is Aerosmith drummer Joey Kramer, who suffered second-degree burns after his Ferrari caught fire at a Scituate gas station in 1998 while the engine was running. A crack in the car's fuel line was to blame.

Now, what about cellphones? During my last trip to the gas station I jotted down the warning about mobile phones. "FAILURE TO FOLLOW THESE WARNINGS COULD CAUSE SERIOUS INJURY OR DEATH," it read. "TURN OFF CELLPHONE AND OTHER ELECTRONIC DEVICES."

Sounds fairly convincing, but it turns out that Massachusetts does not have a single law against using your cellphone at the pump.

Here's an even bigger surprise: The fire marshal 's office says such warnings are unsubstantiated and can be ignored.

"That is such an urban legend," said Jennifer Mieth, spokeswoman for the fire marshal's office. "I don't know how this took off. Our research is that although static electricity is a concern while fueling . . . the cellphone itself does not have the ability to create a spark. It's out there from a lot of people who should know better."

If you're still in doubt, simply touch your car before fueling to discharge whatever static electricity you may be carrying, she said.

Mieth and Nice rattled off answers to the rest of my questions, too, such as whether it's illegal to stretch a gas hose across your car to reach an opposite-side tank (answer: no), whether children can pump gas at a self-service station (answer: they must be at least 16), and whether the law requires special care when taking home a can of gas for your lawnmower (answer: no, but you wouldn't want it in the front seat because of the fumes).
Paul O'Connell, executive director of the New England Service Station and Automotive Repair Association, added one.

"When you're fueling a vehicle, you're supposed to remain at the vehicle until finished. You're not supposed to put something like a gas cap to hold the clip up while you go in and do your business," he said. "People get upset about that , but you can't do it. The nozzle and clip could break, and if you don't notice it you could have a major spill."
What kind of trouble can you get into for breaking gas station rules? Not much, actually. Regulations require service station owners to police their own property, and if a customer leaves her engine running or smokes a cigarette or has her 12-year-old handle the nozzle while fueling , the gas station owner is at fault, fire officials said.

"That's one of the things the clerk is supposed to do. If someone has their engine running they are required to shut off the pump," Mieth said. "The station can be fined or, more important , they can lose their license -- particularly when you're talking about self-serve gas stations. Often when we have problems with the gas station not abiding by the regulation , they will be put on full-serve status only."

So, you won't get a ticket for breaking the rules. But you could put yourself and others at risk, and you might -- or should -- be refused service. And really, on a cold winter's day, who wants that?